The present invention relates to synchro control and more particularly to multiplexing techniques for synchro drivers (transmitters).
Synchros are well-known in the prior art and are used to drive and control a variery of instruments in response to electrical excitation. By way of example, in many avionic systems synchros are employed to provide shaft rotation for controlling various aircraft instruments for display and control. In such instances, the prior art typically employs a plurality of synchros and servos for various devices in the aircraft. Conventional solid-state synchro drivers designed to control the excitation of the windings of a synchro receiver often have limited applications because of different requirements for providing sufficient drive for heavy mismatched loads and proper damping for light single loads. In many applications requiring both, conventional synchro drivers and designs sacrifice one capability for achieving the other. As a result, the application of synchro systems to a variety of aircraft environments is often very limited.
In addition to the above, in many advanced avionics systems employing synchro controls, there is a continuing need to reduce size, weight and power requirements of the instrument and control systems. Using conventional synchro systems, the power supply and driver are required to have a capacity sufficient to meet all of the power and output requirements regardless of the synchro load. Thus, the driver and power supply are required to handle the average power dissipation regardless of the size of the load. As a result, many synchro driving systems cannot meet the spectrum of loading conditions required in current aircraft without a specific tailoring of the drive circuitry or the aircraft system. In any event, such synchro systems necessarily are constructed to handle the maximum power requirements of the system, thereby resulting in the dissipation of significant power regardless of the number or type of synchros being driven.
In many high technology systems including Tacan, VOR, DME, etc., there is still a need for the use of synchro systems and synchro drives. However, in view of the weight, cost and miniaturization requirements of many of the systems, there is a continuing need to provide less costly, more efficient, and less complex circuitry associated with synchro functions and control. There is therefore a continuing need to provide synchro systems and synchro drives which may be applied in a variety of aircraft and other systems requiring synchro control.
Accordingly, the present invention has been developed to overcome the specific shortcomings of the above-known and similar techniques and to provide an improved synchro system and drive having a variety of applications.